When operating a horizontal pressure filter, the filter cakes formed within the filter chambers are often washed using a washing liquid. As the washing liquid is typically fed to the filter chamber via a partially common flow route with the filtrate outlet, any unused washing liquid remaining in the flow route is flushed away by the filtrate during the filtration cycle and hence, can not be used.
However, washing liquid may be a valuable process medium, particularly when condensate is used, because a lot of energy has been consumed to produce the condensate. Moreover, washing liquid may be regarded as valuable resource when the horizontal pressure filter is operated at a remote location, where all resources are scarce, or when an exotic washing liquid is used, for example.